The invention relates to a device for clamping and/or unclamping of tools, comprising a tool shaft in a tool chuck by means of a shrink connection between the tool chuck and the tool shaft.
A device of said type is known e.g. from the German Patent Application DE 103 48 880 A1, which describes the basic configuration and the function of such a device in detail, and which is therefore incorporated by reference into the present patent application.
A general problem of such devices is cooling the tool chuck back down, which has been heated up for clamping or unclamping. This is on the one hand, because the time required for cooling tends to increase the overall time required for the tool change until an operable tool is provided again, on the other hand, because manual removal of tool clamping chucks, which are still hot, is associated with a substantial accident risk.
Therefore, it has already been considered to provide cooling by means of solid cooling bodies, this means by bringing the tool chuck in close contact with another solid body with good heat conducting properties, into which the heat stored in the tool chuck is transferred quickly.
However, such cooling is difficult to accomplish in practical applications. A close surface contact between the chuck and the cooling body has to exist, since heat can only be transferred efficiently that way. The tool chucks or their sleeve sections performing the actual clamping have to have a conical outer contour, since only this way, a sufficiently close contact can be established. With cylindrical chucks, establishing the required surface contact is difficult. In any case, the cooling body and the chuck have to be adjusted to one another. A real integration of the cooling body into the coil unit is not possible. Heating and cooling thus has to be performed at different places, consequently hot chucks need to be handled. It is very difficult to automate such cooling completely or at least to a high extent.
In practical applications, therefore typically, the cooling is performed with water, so that the chuck is removed from the clamping device and submerged in water or showered with water. Also this has significant disadvantages, since in turn, integration into the coil unit is hardly possible, but again the hot chuck has to be handled. Even more so with such cooling, a substantial or complete automation is hardly possible. Furthermore, the whole chuck becomes wet. It has to be cautiously dried subsequently, which is complex. Overall, also for such cooling, a long drying cycle is required.